News

‘Ladder’ device allows fish to swim Lancashire waters

JUVENILE eels which have been on a 3,338-mile journey to mature in Lancashire waters have been given a helping hand by a new engineering project.

Elvers arrive on the county’s coast in early summer after spawning in the Sargasso Sea, near Bermuda, and build themselves up in freshwater rivers like the Ribble, Calder and Hodder before returning to the West Indies as fully-developed silver eels.

But officers from the Ribble Rivers Trust and Environment Agency had discovered that the elvers were facing difficulties reaching the headwaters of the Ribble and Hodder due to a number of hydrometric station weirs en-route.

Work has now been undertaken to develop ‘eel passes’ on the Ribble at Henthorn, and Croasdale Beck, near Slaidburn, close to the top of the Hodder, to ease the passage of the elver population. Similar initiatives have been completed at Settle and Langcliffe further upstream.

Fisheries scientist Gareth Jones said: “These weirs were originally conceived to aid in the measurement of water flows and levels and continue to function for this purpose.

“Unfortunately, they also present significant barriers to fish due to their gradient, shape and change in water flow. Fish species with reduced swimming abilities such as elvers are particularly constrained and so we sought a solution.”

Working with partners at ACE Engineering, the trust and agency developed a bypass channel filled with bristles, through which water is pumped, helping elvers to circumnavigate the weirs.

Supported by solar-powered pumps, they will usually be triggered during nightfall, when elvers typically migrate, and are positioned close to river banks to avoid would-be predators.

Mr Jones said everyone from angling clubs to walkers assisted with regular monitoring of fish and eel populations across the Ribble catchment area and it was hoped the project would see an increase in elvers in the upper reaches this year.

Eels can be found in many urban waterways such as Colne Water and the Brun and Calder through Burnley centre.